Research On Vibration Damping Technology Of Lightweighted And High-resolution Space Optical Camera

With the continuous advancement of space optical remote sensing technology,space cameras are developing towards high resolution and light weight.The space camera along with the satellite is subjected to sinusoidal and random vibrations during launch.The structural deformation and micro-stress of the space camera caused by the vibration will cause the misalignment and optical surface shape error of the optical components,which will affect the image quality in orbit.Therefore,studying the vibration damping technology of the space optical camera in the active stage of the launch has important scientific value and engineering significance.In this paper,combined with the national model project,the vibration damping system of the coaxial dual-reflection array video imaging space camera with a resolution of 0.8 meters and a mass of 25kg is studied,and metal rubber and silicone rubber are used to explore the vibration reduction technology of space optical cameras.Firstly,the differential equations of the kinetic models of the metal rubber and silicone rubber are derived from the constitutive models of the metal rubber and silicone rubber,the transfer function and kinetic amplification coefficient of the excitation displacement and response displacement of the metal rubber and silicone rubber damping system are analyzed,Combined with the kinetic analysis of metal rubber,the material parameters of metal rubber is obtained.Next,design the metal rubber vibration absorber and the silicone rubber vibration absorber for the space camera.Finally,the metal rubber and silicone rubber were tested to obtain the static and kinetic characteristics of the metal rubber and the temperature spectrum of the silicone rubber.In order to verify the accuracy of the theoretical modeling,the finite element models are established for space cameras without shock absorbers,with metal rubber vibration absorber and with silicone rubber vibration absorber.The static analysis,integrated optical-mechanical analysis,modal analysis,frequency response analysis and random vibration response analysis are carried out for the three kinds of space optical cameras,The results of finite element analysis show that the metal rubber vibration absorber and silicone rubber vibration absorber attenuate random vibration response,the metal rubber vibration absorber meets the structural design requirements of space camera,but the space camera does not meet the natural frequency requirements after installing the silicone rubber vibration absorber.The finite element simulation results verify the accuracy of the theoretical analysis.In order to test the accuracy of theoretical modeling and finite element simulation,the sinusoidal sweep test,sinusoidal vibration test and random vibration test were carried out for the space camera without shock absorber,with metal rubber vibration absorber and with silicone rubber vibration absorber.the test results show that the first-order natural frequencies of space cameras without vibration absorbers and equipped with metal rubber vibration absorber in X,Y,and Z directions are all above 100Hz,far away from the satellite natural frequency value,and no resonance occurs in the ground sinusoidal sweep test,while the space camera with silicone rubber vibration absorber does not meet the requirements of natural frequency of space camera;The input excitation response of the coaxial dual-reflection space camera in the X,Y and Z directions is 4.98grms in the random vibration test,the vibration responses of space camera secondary mirror with metal rubber damping system in X,Y and Z directions are 3.381grms,2.884grms and 1.969grms respectively.the vibration responses of space camera secondary mirror with silicone rubber damping system in X,Y and Z directions are 3.167grms and 1.969grms and 3.195grms respectively.The test results verify that the metal rubber vibration absorber and silicone rubber vibration absorber have significant damping effect,which has reference value for the design of the same type of space camera damping structure.The test results are similar to the finite element analysis results,which proves that the theoretical modeling is reasonable and accurate.In order to study the law of vibration reduction performance of metal rubber and silicone rubber,vibration tests with different vibration magnitude and different bearing weight were carried out.It was concluded that the damping performance of metal rubber increased with the bearing weight,and the relationship between silicone rubber and metal rubber with the change of vibration magnitude was analyzed,These conclusions provide a basis for the design of vibration absorber parameters of space camera or other spacecraft.